Genotype x Environment interactions in Pinus pinaster at age 10 in a multi-environment trial in Portugal: a maximum likelihood approach

To study adaptive variation and genotype x environment interactions (GE) of 30 populations from Portugal, Spain, France and Australia, we evaluated total height, diameter, stem form and survival in a multi-environment provenance trial in Portugal, 10 y after plantation, using the restricted maximum likelihood (REML) approach. Significant differentiation was found among populations and also among seedlots from Portugal, populations from different altitude classes and from different provenance regions. Seed orchards showed significantly better growth and stem form. GE interaction was significant for all traits which indicates the existence of differences on phenotypic plasticity among populations, and displayed a pattern that could be related to general or specific adaptation of populations, and/or to human-mediated germplasm transfer. Seed orchards, and the Moncao and Leiria populations showed generally better growth and stem form, and some high altitude populations ranked higher in growth or survival (Braganca, S. Pedro do Sul, Manteigas-Pma30) at the high-altitude Montalegre site. There was a lack of genetic uniformity among populations of the same provenance region. Tentative recommendations are made for afforestation, breeding and conservation.